This invention relates to a connector examination device and method for detecting improper attachment of a metal terminal inserted in a connector housing. The invention also relates to a metal terminal-correcting jig and a method for mounting a metal terminal, disposed in an improperly-inserted position, in a properly-inserted position, and to a connector correction device provided with the jig.
Generally, a connector comprises a connector housing of a plastics material in which metal terminals, each fixedly secured to one end of a wire, are mounted, and each metal terminal is retained against withdrawal by a lance (elastic retaining pawl) formed integrally within the connector housing. When the metal terminal is inserted into the connector housing, the lance is flexed downwardly toward a flexing space until the metal terminal is inserted into a proper position, at which point the lance is elastically restored to engage a void formed along a bottom surface of the metal terminal, thereby preventing withdrawal of the metal terminal.
With this type of terminal withdrawal prevention construction, a certain degree of a frictional force acts between the metal terminal and the lance when the metal terminal is inserted. The frictional force is of such a degree that the metal terminal cannot be inserted into the housing any further, which may give the impression to an operator that the terminal is reliably secured by the lance, even though it is not properly inserted into the housing. Accordingly, the operator, engaged in the inserting operation, may misunderstand that complete insertion has been achieved, and may stop the inserting operation before the lance actually engages the terminal.
However, if the metal terminal is not completely inserted into the proper position where the metal terminal engages the lance in the connector housing, the metal terminal can become withdrawn from the housing during use. Therefore it is necessary to preliminarily inspect the terminal connections to correct any improperly inserted or incompletely connected terminals.
Recently, various kinds of connector examination devices have been developed for detecting improper attachment of a metal terminal. The present applicant filed an application (Japanese Patent Application No. 5-281716) shown in FIG. 7. In this construction, a lance check pin 51 is provided in a projected manner in opposed relation to each lance 34 in a connector 60, and the lance check pin 51 is adapted to be inserted into a lance flexing space 63 formed in a connector housing 62. When a metal terminal 33 is completely inserted into a proper position, the lance check pin 51, inserted in the lance flexing space 63, does not strike against the lance 34, but is brought into underlying relation with the lance, as shown at an upper stage in FIG. 7. When the metal terminal 33 is in an improperly-attached condition, the lance check pin 51 strikes against the distal end of the lance 34 that is elastically deformed in the lance flexing space 63, as shown at a lower stage in FIG. 7. In this construction, when the metal terminal 33 is in an improperly-attached condition, with the lance 34 disposed in the lance flexing space 63, the lance check pin 51 strikes against the distal end of the lance 34. Accordingly, the check pin 51 cannot be positioned beneath the lance 34. As a result, improper attachment of the metal terminal 33 occurs.
For molding reasons, even when the metal terminal 33 is completely inserted into the proper position, with the lance 34 substantially retracted from the lance flexing space 63 and into the terminal 33, the lance 34 still projects slightly inwardly towards an inner wall surface of the lance flexing space 63. In this connection, a distal end portion 51a of the lance check pin 51 is made smaller in thickness than the lance flexing space 63 so that the lance check pin can be brought into underlying relation to the lance 34. Therefore, a gap is formed between the distal end portion 51a of the lance check pin 51 and the bottom portion of the terminal 33.
Therefore, it is possible that when the lance check pin 51 is inserted into the lance flexing space 63, the distal end portion 51a of the lance check pin 51 is inserted into the lance flexing space 63 in a bent, deformed manner, or the lance check pin 51 is inserted obliquely. In such a situation, even when the metal terminal 33 is completely inserted into the proper position, with the lance 34 fully retracted from the lance flexing space 63, the distal end portion 51a of the lance check pin 51 can strike against the slightly-projected portion of the lance 34. As a result, despite the fact that the metal terminal 33 is disposed in the proper position, the lance check pin 51 can not reach the position beneath the lance 34, and therefore it may be erroneously judged that the metal terminal 33 is in an improperly-attached condition.
In addition, there have been several proposed devices to confirm and inspect the position of the terminal. For example, a retainer that engages the metal terminal (with which the lance is also engaged) is inserted into the housing when an operator believes that the terminal is in the properly-inserted position, thus providing, together with the lance, a second engagement if the terminal is inserted to a depth where the lance engages a void or hole in the terminal. The retainer is provisionally attached to the connector before the metal terminals are inserted, and in this condition, after the metal terminals are inserted, the retainer is moved into a completely-attached position to engage the metal terminals.
At this time, if the metal terminal is disposed in an improperly-inserted position (short of the properly-inserted position), the retainer engages the metal terminal, and can not be moved into the completely-attached position. Thus, the retainer indicates whether the metal terminals have bee inserted into the properly-inserted position. If it is judged that any metal terminal has not been inserted into the properly-inserted position, i.e., the retainer engages the metal terminal rather than a recess or the void of the metal terminal, the metal terminal is removed and tried again.
In the above method in which the retainer is used to determine proper positioning of the terminals, the retainer, mounted on the connector in the completely-attached position, remains connected to the connector, and even after the inspecting of the terminal is complete, the retainers remain mounted on the connector housings. Therefore, inspection of the terminals requires a permanently mounted retainer for each terminal and therefore the cost and number of the parts required for inspecting terminals is high.
Moreover, the retainer merely judges whether the metal terminal is disposed in the properly-inserted position or an improperly-inserted position, and when it is judged that the metal terminal is in the improperly-inserted position, an operator is required to remove the terminal and attempt to reinsert the terminal. After the retainer is attached again, the condition of insertion of the metal terminals is rechecked, thus requiring even more time and labor. Therefore, the overall efficiency of the metal terminal-inserting operation suffers.